title: Isolation and characterization of the circulating form of human endostatin.
abstract: Recently, fragments of extracellular proteins, including endostatin, were defined as a novel group of angiogenesis inhibitors. In this study, human plasma equivalent hemofiltrate was used as a source for the purification of high molecular weight peptides (10-20 kDa), and the isolation and identification of circulating human endostatin are described. The purification of this C-terminal fragment of collagen alpha1(XVIII) was guided by MALDI-MS and the exact molecular mass determined by ESI-MS was found to be 18 494 Da. N-terminal sequencing revealed the identity of this putative angiogenesis inhibitor and its close relation to mouse endostatin. The cysteine residues 1-3 and 2-4 in the molecule are linked by disulfide bridges. In vitro biological characterization of the native protein demonstrated no anti-proliferative activity on different endothelial cell types. These data indicate that human endostatin, which is a putative angiogenesis inhibitor, is present in the circulation.
authors.affiliation: Lower Saxony Institute for Peptide Research (IPF), Hannover, Germany.
authors.forename: L
authors.initials: L
authors.lastname: Ständker
authors.forename: M
authors.initials: M
authors.lastname: Schrader
authors.forename: S M
authors.initials: SM
authors.lastname: Kanse
authors.forename: M
authors.initials: M
authors.lastname: Jürgens
authors.forename: W G
authors.initials: WG
authors.lastname: Forssmann
authors.forename: K T
authors.initials: KT
authors.lastname: Preissner
mesh_terms: D000595:Amino Acid Sequence; D002452:Cell Count / Q000187:drug effects; D003094:Collagen / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D043170:Collagen Type XVIII; D043169:Endostatins; D004730:Endothelium, Vascular / Q000187:drug effects; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D006440:Hemofiltration; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D018919:Neovascularization, Physiologic; D010446:Peptide Fragments / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D043170:Collagen Type XVIII; D043169:Endostatins; D010446:Peptide Fragments; D016222:Fibroblast Growth Factor 2; D003094:Collagen